Field of the Invention
The present invention relates to a transmission control unit for use in the transmission and reception of data between electronic devices such as a facsimile and a personal computer incorporating a modulator/demodulator (MODEM) over a telephone.
There is a conventional technology of the transmission and reception of data between electronic devices via a telephone.
U.S. Pat. Nos. 4,599,491 issued Jul. 8, 1986 discloses a method and apparatus for converting direct coupled data devices to acoustic coupled devices. This apparatus consists of an acoustic coupler and associated electronics to provide acoustic coupling to a telephone handset and to connect to a direct connect modem or other data device to allow operation of the direct connect modem in most modes as if directly connected to a telephone line.
However, since this apparatus requires an acoustic coupling, the operation is required for securely coupling the acoustic coupler to the telephone handset during data transmission, and moreover acoustic noise is apt to get mixed into the acoustic data to and from the handset, which results in adversely affecting the accuracy of data communication.